Electrical switch

ABSTRACT

An electrical switch comprises a plurality of fixed contacts and a movable contact mounted on a carrier. There is provided an operating member which effects movement of the carrier between a first position in which the movable contact electrically interconnects the fixed contacts and a second position in which the movable contact is spaced from the fixed contacts. The switch also includes further fixed contacts which are associated with a resilient conducting member. The resilient conducting member is electrically connected to a first of the further fixed contacts and is biassed to be connected electrically with a second of the further fixed contacts when the carrier is in one of its positions. The carrier includes a projection which, when the carrier is in its other position, engages the resilient member, and urges it out of connection with the second of the further fixed contacts and into electrical connection with a third of the further fixed contacts.

United States Patent [19]: i

Lewis July 23, 1974 ELECTRICAL SWITCH [57] ABSTRACT [75] Inventor: Ke'thLewiS"Bum1ey1 England An electrical switch comprises a plurality offixed 73 Assignee; The Lucas Electrical Company contacts and a movablecontact mounted on a carrier. Limited, Birmingham England There isprovidteld an operating member which effects movement of t e carrierbetween a irst osition in [22] Fled: 1973 which the movable contactelectrically int rconnects [21] L 344,552 the fixed contacts and asecond position in which-the movable contact is spaced from the fixedcontacts. 52 U.S. Cl. 200/67 G The Switch alsoiiiicludes further fixedcontacts which [511 int. Cl. H01h 5/18 are associated with a resilientconducting member- [58] Field of Search 200/67 DA, 67 o, 153 L Theresilient conducting member is e t y nected to a first of the furtherfixed contacts and is bi- [56] R f n it d assed tobe connectedelectrically with a second of the UNITED STATES PATENTS further fixedcontacts when the carrier is in one of its I 4 positions. The carrierincludes .a projection which, when the carrier is in its other position,engages the T V A 'f I resilient member, and urges it out of connectionwith FQREIGN PATENTS 0R APPLICATIONS the second of the further fixed contacts an d into elec- 803,314 10/1958 Great Britain 200/67 G PrimaryExaminer-RoyN. Envall, Jr. Attorney, Agent, or Firm-Holman & Sterntrical. connection with a third of the further fixed.

' contacts.

I 5 Claims, 2 Drawing Figures PATENTED M2319 FIG.2.

1 ELECTRICAL SWITCH This invention relates to electrical switches.

According to the present invention, there is provided an electricalswitch comprising a plurality of fixed contacts, a movable contactmounted on a carrier, an operating member for effecting movement of thecarrier between a first position in which the movable contactelectrically interconnects the fixed contacts and a second position inwhich the movable contact is spaced from the fixed contacts, a set offurther fixed contacts, a resilient, conductingmember connected to afirst of the further fixed contacts and biassed to be connectedelectrically with a second of the further fixed contacts when thecarrier is in one of its two positions, andmeans on the carrier, when inits other position, for urging the resilient member out of electricalconnection with the second of the first fixed contacts and intoelectrical connection with a third of the further fixed contacts. i

Preferably, means are provided for limiting the contact pressure betweenthe resilient member and the third of the further fixed contacts. Suchmeans may be provided by a projection on the carrier which engagesagainst a stop when the carrier is in its said other position.

Most advantageously, the said other position of the carrier is theaforementioned second position of the carrier.

Preferably also, a conducting blade spaced at one end fromthe third ofthe further fixed contacts and'attached to the'second of the furtherfixed contacts en gages the resilient member when the latter is in itsbiassed position so as to provide the electrical connection between theresilient member and the second of the further fixed contacts.

An embodiment of the present invention will now be describpd, by way ofexample, with reference to the accompanying drawing, in which:

FIG. 1, is a cut-away sectional view of part of an electrical switchaccording to the present invention,- and FIG. 2 is a plan view of partof the switch shown in FIG. 1, in which the fixed contact layout isillustrated.

Referring to the drawing, the electrical switch com-.

prises a body 1 in which are mounted a set of four fixed contacts 2, 3,4 and 5 and a further set of three fixed .contacts 6, '7- and 8.Attached to each of the fixed contacts 4 and 5 is a plate 9 having anupstanding pivot portion 10. The plates 9 are electrically conductive. Acarrier 11 is mounted on the pivot portions 10 so as to be pivotalrelative thereto and has on its undersurface a contact blade 12 whichextends between a portion of the carrier adjacent the pivot portions 10and a location at which it can engage fixed contacts 2 and 3. In theposition shown in FIG. 1, the contact carrier 11 is in a first positionin which the contact blade 12 provides electrical connection between allof the fixed contacts 2, 3, 4 and 5. The carrier 11 is provided with apivot projection 13 disposed adjacent a pivot surface 14 on the body 1.A pivotal operating member 15 engages the carrier 11 and can be manuallymoved over the surface of carrier 11 to effect movement of the latteraway from its first position to a second position in which the carrier11 has pivoted about pivot projection 13 on pivot Surface 14. In thesecond position of the carrier 11, it is no longer resting on pivotportions 10 so that the contact blade 12 is no longer in contact withthe pivot portions 12 or with the fixed contacts 2 and 3. It is to beappreciatedthat the pivot projection 13 is not in contact with the pivotsurface 14 but is spaced slightly above the latter when the carrier isin its first position.

The end of the carrier remote from the end at which lies the contactblade 12 is provided with a projection 16, and a further projection 17,which is rather deeper than projection 16, is provided between pivotprojection 13 and projection 16. The purpose of these two projections 16and 17. will be described hereinafter.

Attached to fixed contact 7 is one arm of an L- shaped conducting blade18 whose other arm terminates in a contact 19 which is spaced verticallyabove fixed contact 8. An electrically conducting blade spring .20 issecured to fixed contact 6 and has a movable contact portion 21 which isresiliently biassed into a position in which it is in electricalengagement with contact 19. Thus, the fixed contact 6 is normally inelectrical connection with fixed contact 7 through blade spring 20 andconducting blade 18.

In operation, when the carrier 11 is moved by means of the operatingmember 15 into its second position, i.e., that position in which thecontact blade 12 is spaced from fixed contacts 2, 3, 4 and S, thefurther projection 17 on the carrier 11 engages the blade spring 20 andurges the contact 21 thereon away from contact 19 and into electricalconnection with fixed contact 8. During this movement, the projection 16on the carrier 11 moves towards fixed. contact 7 and abuts thereagainstso asto limit the amount by which the contact carrier. 11 can bepivoted. In this manner, the contact pressure between contact 21 andfixed contact 8 is limited, thereby preventing the blade spring 20 frombeing overstressed. It is to be appreciated that the contact carrier 11is moulded from a synthetic plastics material and therefore there is norisk of short circuiting occurring when projection 16 abuts fixedcontact 7 or when the further projection 17 engages the blade spring 20.

Thus, in the firstposition of-the carrier 11, electrical connection ismade between fixed contacts 2, 3, 4 and 5 and also between fixedcontacts 6 and 7 whereas in the second position of the carrier 11, onlyconnection is made between fixed contact 6 and fixed contact 8.

I claim: 1. An electrical switch comprising a plurality of fixedcontacts, a movable contact mounted on a carrier, an

operating member for effecting movement of the carrier between a firstposition in which the movable contact electrically interconnects thefixed contacts and a second position in which the movable contact isspaced from the fixed contacts, a. set of further fixed contacts, aresilient, conducting member connected to a first of the further fixedcontacts and biassed to be connected electrically with a second of thefurther fixed contacts when the carrier is in one of its two posi tions,and means on the carrier, when in its other position, for urging theresilient member out of electrical connection with the second of thefurther fixed contacts and into electrical connection with a third ofthe further fixed contacts.

2. An electrical switch as claimed in claim 1, wherein means areprovided for limiting the contact pressure between the resilient memberand the third of the further fixed contacts.

a conducting blade spaced at one end from the third of the further fixedcontacts and attached to the second of the further fixed contactsengages the resilient member when the latter is in its biassed positionso as to provide the electrical connection between the resilient memberand the second of the further fixed contacts.

1. An electrical switch comprising a plurality of fixed contacts, amovable contact mounted on a carrier, an operating member for effectingmovement of the carrier between a first position in which the movablecontact electrically interconnects the fixed contacts and a secondposition in which the movable contact is spaced from the fixed contacts,a set of further fixed contacts, a resilient, conducting memberconnected to a first of the further fixed contacts and biassed to beconnected electrically with a second of the further fixed contacts whenthe carrier is in one of its two positions, and means on the carrier,when in its other position, for urging the resilient member out ofelectrical connection with the second of the further fixed contacts andinto electrical connection with a third of the further fixed contacts.2. An electrical switch as claimed in claim 1, wherein means areProvided for limiting the contact pressure between the resilient memberand the third of the further fixed contacts.
 3. An electrical switch asclaimed in claim 2, wherein the limiting means is provided by aprojection of the carrier which engages against a stop when the carrieris in its other position.
 4. An electrical switch as claimed in claim 1,wherein the said other portion of the carrier is the said secondposition of the carrier.
 5. An electrical switch as claimed in claim 1,wherein a conducting blade spaced at one end from the third of thefurther fixed contacts and attached to the second of the further fixedcontacts engages the resilient member when the latter is in its biassedposition so as to provide the electrical connection between theresilient member and the second of the further fixed contacts.